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Overview of Polymer and Solid Electrolytes: Towards All Solid-State Batteries
Published in Władysław Wieczorek, Janusz Płocharski, Designing Electrolytes for Lithium-Ion and Post-Lithium Batteries, 2021
Michał Marzantowicz, Michał Struzik
Effective dissociation of lithium salts is possible also by nitrogen atoms from nitrile groups [121]. A representative of this family of polymers is poly(acrylonitrile) (PAN). This matrix represents good electrochemical stability toward oxidation, but the elevated glass transition temperature (125°C) and a melting point situated above 300°C practically exclude polymer chains from active support of ionic conductivity [122]. Moreover, lithium cations strongly coordinated by the polymer chain may in fact become immobile. PAN-based electrolytes obtained by the solvent casting method have exhibited promising values of conductivity [123, 124], but this effect can be attributed to the residual solvent left from the synthesis process. Solvent-free electrolytes have rather low conductivity [125]. PAN is often used as a structural skeleton for other classes of polymer electrolytes, such as polymer-in-salt or polymer-in-gel electrolytes.
Electrospun Carbon Nanofibers for Energy Conversion and Storage
Published in Changjian Zhou, Min Zhang, Cary Y. Yang, Nanocarbon Electronics, 2020
As environmental pollution has become a serious problem, developing energy conversion and storage devices to support the utilization of renewable energy technologies is increasingly important. Lithium-ion batteries (LIBs) and solar cells (SCs) are representative examples. Better LIBs with high energy density, high power density, long cycle life, and improved safety are in high demands. Electrode materials are the key to define the LIB performance. Carbon materials have been a key component in today’s LIBs due to their chemical stability, excellent electrical conductivities, and large surface areas. Among them, carbon nanofibers (CNFs) have attracted particular attentions. Initially, carbon fibers were developed as one of the important industrial materials using various carbon precursors, including polyacrylonitrile (PAN) through a melt spinning process. PAN was later commonly used as a polymeric precursor in electrospinning processes, which can be converted into CNFs through oxidation stabilization and carbonization processes.
Fibre-reinforced composite materials
Published in William Bolton, R.A. Higgins, Materials for Engineers and Technicians, 2020
The bulk of carbon fibre is manufactured by the heat-treatment of polyacrylonitrile (PAN) filament. The process takes place in three stages in an inert atmosphere: A low-temperature treatment at 220°C. This promotes cross-linking between adjacent molecules so that filaments do not melt during subsequent high-temperature treatments.The temperature is raised to 900°C to ‘carbonise’ the filaments. Decomposition takes place as all single atoms and ‘side groups' are ‘stripped’ from the molecules, leaving a ‘skeleton’ of carbon atoms in a graphite-like structure.The heat-treatment temperature is then raised to produce the desired combination of properties. Lower temperatures (1300–1500°C) produce fibres of high tensile strength and low modulus, whilst higher temperatures (2000–3000°C) provides fibres of low strength but high modulus.
Thermally oxidized PAN as photocatalyst support layer for VOCs removal
Published in The Journal of The Textile Institute, 2023
Qiming Wang, Wenli Bai, Xi Lu, Jinfeng Wang, Esfandiar Pakdel, Zhicai Yu, Yongming Cui, Qingtao Liu
Polyacrylonitrile (PAN) is a low-cost homopolymer, usually synthesized by a simple process of free radical polymerization of acrylonitrile at a low temperature (El-Ghamaz et al., 2013). It has good resistance to most organic solvents, inorganic acids and oxidizing agents such as chlorides and hydrogen peroxide (Gao et al., 2016). In terms of technical applications, PAN has been extensively studied as hollow fiber membranes for water treatment and purification, filter materials for smoke elimination, nano-sensors and biomedical applications (Martín et al., 2018; Ren et al., 2009). PAN nonwovens have some advantages, such as porous structure and large specific surface area, which can be used as a support material or template for immobilization of various photocatalysts (Go et al., 2016). This can result in enhancing the interaction between photocatalysts and pollutants, and improving their re-useability (Liu et al., 2010; Wang et al., 2013; Zhang et al., 2012). Thermal oxidation is one of the steps in the conversion of polyacrylonitrile into carbon fibers (Moskowitz et al., 2020). During a thermal-oxidation process, polyacrylonitrile undergoes a cyclization reaction to convert linear PAN macromolecules into a trapezoidal structure that is thermally stable (Fu et al., 2017).
Furnace for in-situ characterization of the preoxidation of polyacrylonitrile (PAN) fibers by wide angle X-ray scattering (WAXS)
Published in Instrumentation Science & Technology, 2021
Rongchao Chen, Weifeng Huang, Zhihong Li, Ying Shi, Li-Zhi Liu, Dongfeng Li, Baoliang Lv
Polyacrylonitrile (PAN) based carbon fibers have wide applications for superior properties such as high tensile strength, high modulus and light weight.[1,2] Preoxidation is an important intermediate process in the production of carbon fibers.[3] In the preoxidation step below 300 °C, chemical reactions such as cyclization, oxidation and dehydrogenation occur successively,[4] which gradually transform the one-dimensional linear macromolecular chain of polyacrylonitrile fibers into the two-dimensional ladder structure of preoxidized fibers. The heat resistance of the fibers is improved and the embryo of the graphite-like lamellar structure is formed during this process.[5,6]
Carbon nano-onion-filled polyacrylonitrile/polyethylenimine foams: structure, characteristics, and ion detoxification studies
Published in Journal of the Chinese Advanced Materials Society, 2018
Polyacrylonitrile (PAN) is an important thermoplastic polymer having low density, high strength, modulus of elasticity, and thermal stability.[1] PAN can also absorb toxic metal ions, so can be used for water treatment. Polyacrylonitrile resins are usually produced from the monomers containing acrylonitrile unit through free radical polymerization. PAN has been commercially used as precursor for fibers, films, membranes, foams, etc.[2,3] Carbon nanofiller such as carbon nanotube, graphene, graphene oxide, nanodiamond, etc. reinforced polyacrylonitrile nanocomposite have exhibited significant improvement in mechanical robustness, thermal stability, electrical conductivity, etc. for various technical applications.[4–6] Carbon nano-onion (CNO) is a newly developed carbon nanomaterial.[7] CNO has 0-D structure with small diameter of <10 nm. Structure of CNO consists of hollow spherical fullerene core with outer concentric graphene layers.[8,9] In other words, it is a multilayer fullerene structure. It has several superior physical properties to be employed in supercapacitor, solar cell, Li-ion battery, dielectric and biomedical materials.[10,11] However, carbon nano-onion has not been opted as nanofiller for PAN-based nanomaterials so far. Few attempts have been found in literature regarding microcellular PAN foam materials.[12,13] PAN foam has been used as precursor for variety of applications such as fuel cell, supercapacitor, sensor and other energy relevance.[2,14,15] Moreover, polymer-based nanostructures have been successfully employed in ion-selective application for the removal of environmental toxicity.[16–20] In this regard, PAN foams have not been employed yet. To the best of knowledge, PAN foam with carbon nano-onion nanofiller has not been reported in literature so far. In this study, carbon nano-onion has been reinforced in novel polyacrylonitrile/polyethylenimine (PAN/PEI) blend, polyacrylonitrile/polyethylenimine/carbon nano-onion (PAN/PEI/CNO) nanocomposite and their PAN/PEI/CNO foam materials with varying nanofiller loading. Structure, morphology, compression mechanical properties, thermal stability, nonflammability, water uptake characteristics and toxic metal ion removal have been explored in detail using relevant characterization techniques. The importance of CNO nanofiller dispersion and interaction with PAN matrix in nanocomposite and foam forms have been illustrated for high performance materials.